Leukemia and lymphoma are important forms of neoplasia in animals and humans. Advances in biology and treatment of these disorders frequently presage progress in other cancers. Furthermore, the hematopoietic malignancies are often studied as models for normal cell growth and regulation. Recently, there has been considerable progress in leukemia research. Consistent chromosome abnormalities are reported in several forms of leukemia and lymphoma; these abnormalities are correlated with altered expression of oncogenes or developmental genes such as the T-cell receptor. Regulation of normal and abnormal hematopoiesis has also been intensively investigated with striking new results. Growth factors and receptors have been isolated, molecularly cloned, and their relationship to specific oncogenes determined. Recently, transforming genes have been isolated from leukemia cells, and it has been possible to induce leukemia in vitro by the introduction of novel genetic material. Since much recent progress in the areas of oncogenes, chromosomes, and regulation of growth and differentiation have been in the context of normal and malignant hematopoiesis, it is likely that a productive synthesis of these areas of investigation will occur in the area of leukemia/lymphoma research. This conference will review two additional areas of recent progress: the introduction of new genetic information into hematopoietic stem cells, and advances in leukemia treatment. The exchange of scientific information at this conference will yield insights into normal and neoplastic hematopoiesis which translate into novel forms of prevention and treatment of cancer.